A backhoe loader as a work vehicle includes a loader bucket disposed forwards of a vehicle body while including a backhoe disposed rearwards of the vehicle body. Further, an operator's seat disposed in a cab is rotatable while being configured to be oriented forwards during travelling or execution of a work with the loader bucket and be oriented rearwards during execution of a work with the backhoe.
A multi-axis transmission is installed in the backhoe loader as described above. The transmission includes an input shaft to which power is inputted from an engine, an output shaft for outputting power to a wheel and at least an intermediate shaft disposed between the input shaft and the output shaft. Further, each shaft is provided with a hydraulic clutch for switching between forward travelling and rearward travelling and a plurality of hydraulic clutches for switching back and forth among speed stages. It should be noted that the hydraulic clutches are hereinafter simply referred to as “clutches”.
In the conventional transmission, the forward/rearward travelling switching clutch includes a single forward travelling clutch and a single rearward travelling clutch. In such structure, however, the number of gear stages is limited in forward travelling and thus a multiple stage configuration is impossible. Therefore, acceleration performance is not good during travelling in a speed range from a middle speed to a high speed.
In view of the above, it can be considered to implement a multiple stage configuration by increasing the number of speed stage switching clutches. However, with increase in the number of the speed stage switching clutches, the number of components is increased and the transmission is entirely increased in its size. Further, with increase in the number of the speed stage switching clutches, the number of speed stages is increased not only for forward travelling but also for rearward travelling that a multiple stage configuration thereof is unnecessary.
To solve such drawback, a transmission as described in Japan Laid-open Patent Application Publication No. JP-A-H11-230278 has been produced. The transmission described in this publication includes an input shaft, two intermediate shafts and an output shaft. Further, the input shaft is provided with a rearward travelling clutch and a forward travelling lower speed clutch, while one of the intermediate shafts is provided with a forward travelling higher speed clutch. Yet further, three clutches are provided as speed stage switching clutches.
As described above, the transmission described in the above mentioned publication includes the forward travelling lower speed clutch and the forward travelling higher speed clutch as forward travelling lower/higher speed switching clutches, and includes first to third clutches as speed stage switching clutches. Therefore, six speed stages can be obtained in forward travelling and a multiple stage configuration is implemented with a small number of components.